This invention generally relates to a remote control of a spool position of a fluid throttling valve.
In more particular aspects this invention relates to a remote control of the spool of a throttling valve, which includes compensation of positive and negative loads.
In still more particular aspects this invention relates to a remote control of a position of a valve spool, in which due to compensation and flow characteristics of the metering orifice the force acting on the spool is directly proportional to the displacement of the spool from its neutral position.
Remote control of a valve spool, subjected to a throttling action, presents a difficult problem, since the flow forces, well known in the art, to which the throttling valve is subjected are directly proportional to the square root of the pressure differential and to the rate of fluid flow. At large pressure differentials and large rates of flow those flow forces may be equal to hundreds of pounds. If the position of the valve spool is defined by a certain level of control force or control pressure, this position will vary widely with the pressure differential of the throttled fluid.